The Quantum Efficiency of Photosynthesis 

 H • k C0 2 -- H' ■ k'o 2 



85 



(Equation 1) Action of light in 80' xo 2 = 



kco2 

 ko 2 



k' 



CQ2 



k' 



o 2 



{Equation 2) 



H • k<>, — H' • kco 2 



xco 2 = 



ko 2 



k' 



+ 151 /d 



168 »1 



o 2 



k c 



Actinometer : 8.83 //l O, per minute 



1 80 • 8.83 



Quantum efficiency for 2 , 



1 



Quantum efficiency for CO,, 



151 

 80 • 8.83 



Assimilatory quotient, } 

 CO, 



<p 168 



CO, -168 



•o 2 

 = 4/7_ 



= 4.2 



k' 



co 2 



— 1.11 



If V 



O, 



O, + 151 



1-11 is determined for a given cell Suspension, then .\o, and .\'co, can be 



obtained by the pressure changes in light and dark in each Single vessel. For example, in vessel 

 No. 5, the following figures, taken immediately prior to the readings above, were obtained upon 

 illumination with light of an actinometer value of — 5.07 /d O, per minute: 



Vessel No. 5 

 10' dark— 12.5mm 

 10' light-- 2.5 mm J. 10' ] 

 10' dark — 13.0 mm 

 10' light- 1.5 mm 

 10' dark — 10.0 mm 



10.2 mm 

 10' : + 10.0 mm 



20' H' = 20.2 mm 



(Equation 3) Action of light in 20'; xo, == H'— ' 2 , - .20.2-1.62= -32.8 



v ^ ^ COo + 7 k o 2 



Quantum efficiency for O2, 

 Quantum efficiency for CO,, 



co 2 -t- y 



xco2= -1.11 -xo,= - 32.8- -1.11 = -36.4 

 20 ■ 5.07 



1_ 

 9 



32.8 



20 • 5.07 



36.4 



3.1 

 2.8 



PROTOCOL No. 2 



Experiment of V-30-49. 20°C. 630—660 m/i. 5% CO, in air. 270 ,/d of cells per vessel. 



Experiment I. Alternately dark and light each 10'. Actinometer for the red light (total) 5.4 //l 

 O2 per minute. When vessel No. 5 was dark, No. 3 was illuminated and vice versa. 



No. 5 



Constants as in Protocol 1 



10' dark — 10.5 mm 10' light + 0.5 mm 



10' dark 10.0 mm 10' 1 

 10' dark 9.0 mm 10' 1 



10' dark 

 10' dark 

 10' dark 



8.5 mm 10' light 



9.0 mm 10' 1 



ght mm 

 ght 1.5 mm 



ght - 



mm 

 1.0 mm 



8.0 mm 10' light 1.0 mm 



No. 3 

 Constants as in Protocol 1 

 10' dark - 2.0 mm 10' light - 3.0 mm 

 10' dark 3.5 mm 10' light -2.0 mm 



10' dark 2.5 mm 10' light 3.5 mm 



10' dark 2.5 mm 10' light - 3.5 mm 



10' dark mm 10' light - 3.0 mm 



10' dark 1.0 mm 10' light - 5.0 mm 



60' dark 55.0 mm 60' light - 4.0 mm 

 60':H' = 4 + 55 = - 59 mm 



60' dark — 11.5 mm 60' light - 20.0 mm 

 60':H == 20 11.5 = 31.5 mm 



Experiment II: Both vessels were now constantly illuminated with a 100-watt incandescent 

 lamp of nonmeasured* light intensity and red light of measured intensity added for alternating 

 periods of 5'. Actinometer for the red light (total) 5.4 id O2 per minute. 



* But kept constant by a 500-watt voltage regulator. 



